Hammers



April 20, 1965 s. H. MOREL 3,179,344

HAMMERS Filed June 14 1962 Inventor G rg 31. Morel I53 armada, now/$04 United States Patent 3,179,344 HAMNIERS George H. Morel, Crete, Ill., assignor to American Brake Shoe Company, New York, N. a corporation of Delaware Filed June 14, 1962, Ser. No. 202,534 11 Claims. (Cl. 241-197) This invention relates to two-part hammers for a hammer mill, being of the kind wherein a replaceable tip is removably mounted on the lower end of the hammer shank.

It is conventional in the art to construct hammers for a hammer mill with a separable tip which can be replaced when unduly worn. Thus, in actual operation of the mill, it is the tip of the hammer which takes the beating, and the shank merely serves to secure the hammer to the mill shaft for rotation therewith and to present the tip in proper working position within d h 1m l r=---- The parts of a hammer mill are so related as to define an interior circular cavity of relatively narrow width, such being in conformity with the necessity of confining the material to be crushed between the hammer tip and the opposed surfaces of the mill. As a consequence, there is not a great deal of room available for repairing the hammer, and in particular when replacing the tip.

Ideally, it would be desirable to replace the tip without the necessity for removing the entire hammer assembly entailing removing the hammer shank from the shaft which carries the hammer. Moreover, in order to reduce the downtime of the mill to a minimum when replacing the tip, it is advantageous that such replacement be accomplished with a minimum of effort.

It is, therefore, an object of the present invention to interrelate parts of the shank member and replaceable tip member of a two-part hammer of the kind described so that themembers can be easily disassembled, and in particular by a simple movement of the tip in a 'direction normal to the axis of the hammer shank, that is, toward or away from the side of the mill as the case may be; and to secure the members together by a spring detent well protected against abuse. I

Another object of the present invention is to so configure the interrelated parts as to resist the tendency for sections of the hammer to be spread due to the centrifugal forces involved when the hammer is in use.

Other and further objects of the" present invention will be apparent from the following description and claims and are illustrated in the accompanying drawings which, by Way of illustration, show a preferred embodiment of the present invention and the principles thereof and what are now considered to be the best mode for applying these principles. Other embodiments of the invention embodying the same orequivalent principles may be made as desired by those skilled in the art without departing'from the present invention and the purview of the appended claims.

In the drawings:

FIG. 1 is a view partly in elevation and partly in section of a hammer constructed under and in accordance with the present invention;

FIG. 2 is a view illustrating the parts in disassembled relationship, the tip of the hammer being shown as partly broken away;

FIG. 3 is a detail view of a preferred spring element constituting part of the spring detent;

FIG. 4 is a perspective view of a detent boss; and

FIG. 5 is a perspective view of a detent release element.

The hammer 10 of the present invention, FIG. 1, includes a shank member 11 and a related tip member 12 adapted to be removably positioned on the lower end of the shank 11 as viewed in FIG. 1. The lower end of the shank is nested within a recess in the tip which is open at the top of the tip.

The hammer shank or arm 11 is adapted to be secured within a hammer mill for rotation with the rotor of the mill. Usually, the rotor is in the form of a disc or plate having a plurality of shafts or hammer supporting pins of large diameter projecting therefrom, and to this end the shank 11 is formed at the head or upper end thereof with a relatively large opening 14 adapted to receive such a shaft or mill pin.

The tip 12 represents that part of the hammer which acts directly on the material that is to be crushed or comminuted within the mill. As a result, the tip 12 tends to wear rather rapidly, and it becomes necessary periodically to replace the tip.

The shank member 11 and the tip member 12 have complementally interfitting parts slidably related to enable the tip to be slipped on and off the lower end of the shank, that is, the end opposite the opening 14, and such sliding movement, underjthe present invention, is in a direction normal to the longitudinal axis of the shank.

To this end, the lower end of the shank member 11 is provided with a pair of outwardly projecting shoulders or wings 17 and 18 which project outwardly from the opposed vertical slides 19 and 20 of the mill which become the leading and trailing faces of the shank considered with respect to the path of travel of the hammer indicated by the curved arrow in FIG. 1. The

other sides .of the hammer shank, such as the side 21,

FIG. 2 face the sides of the mill.

As shown in FIG. 1, the wings 17 and 18 are posi tioned above the flat lower face 23 representing the remote face of the shank at the end thereof opposite the shaft opening 14. Consequently, the free lower end of the hammer shank is substantially cruciform.

The shoulders 17 and 18 are of dovetail form in cross section for reasons to be explained hereinafter and are adapted to neatly fit in complemental grooves or slots 24 and 25 located within the hammer tip characterized by projections 24A and 25A that have back-drafted or undercut lower surfaces 24' and 25', FIG. 2, complemental to the mating surfaces of the shoulders 17 and 18 of the hammer shank. Thus, the body of the tip 12 is formed with a relatively large recess 26, FIG. 2, extending downwardly thereinto from the flat upper face 28 of the hammer tip. In this connection, it may be noted that the tip is of generous size in comparison to the shank so that there is adequate metal for prolonged use. 1

In addition to the flat upper face 28, the tip includes flat vertical fore and aft faces 30 and 31 which respectively represent leading and trailing impact faces. These faces, depending upon mill rotation, are responsible for impacting and shattering the material fed to the mill.

The faces 30 and 31 at their lower ends are joined by an arcuate lower face 33 or the tip having a curve substantially complemental to the arcuate interior wall of the mill whereat further comminution occurs.

As best shown in FIG. 2, the recess 26 is open at one of the sides of the tip which will face the side plate of the mill. The other side of the recess 26 in the tip is closed by a side wall 32. It may further be observed that the geometry of the recess 26 is fully complemental to the cruciform cross section of the hammer tip at the lower end thereof, and as a consequence the exposed cruciform opening of the tip at the open side thereof shown in top of the mill. along the axis of the shank toward the shaft opening 14, 1 the detent 37 will be moved out of the opening 40 in the -hammer tip to project all the Way into the opening 35.

FIG. 2 can be easily slid onto the lower cruciform end of the shank in a direction normal to the longitudinal axis of the shank.

The centrifugal forces during operation of the mill tend to encourage spreading of the end walls of the hammer 30W and 31W, but in the present instance this is resisted by so orienting the upper surfaces of the projections 17 and 18 as to have the same in planes 17A and 18A sloping downwardly and inwardly toward the faces 19 and 20. In other words, theincluded angle between the face of the hammer shank and the adjacent surface of the projection as 17 is an acute angle. As a consequence, there is a keyor dovetail fit between the ribs 17 and 18 and the related internal surfaces of the tip resisting the tend- .ency of any centrifugal force'to spread the walls 30W and 31W.

A primary feature of the present invention is that the tip is secured against displacement by a spring detent in .a protected position within .the hammer. Nevertheless, the spring detent is one that can be released from the exterior of the hammer incidental to slipping the tip off the shank.

To this end, the hammer shank is formed with an opening or detent mounting recess 35, FIG. 1, located medially of the lower-face 23 thereof and extending upwardly into the shank parallel to the longitudinal axis thereof. A spring element in the form of a coil spring is located within this same opening and represents the spring bias of the spring detent.

The .detentitself is inthe form of a detent boss or block 37 of cylindrical'shape which is normally positioned by the spring 36 in the associated relation of the hammer 7 with an elongated aperture 41 which extends therefrom throughthe lower portion of the hammertip to open at the arcuate'face 33 thereof. The spring 4% enables the detent tobe released by a force ap'plied'from the exterior of the tip. To this end, a detent release or stud 43 is seated inthe opening 40 and includes a part extending throughout substantially the full length of theaperture 41. Thus, the stud or detent release 43 includes a head 43H interposed between the aperture 41 and the detent '37. The detent release 43 additionally includes a stem or pin 43A that fits neatly in the aperture 41.

When the parts are in the assembled relation of FIG. 1,

the spring 36 acts forcefully on the head of the detent in the shank socket 35, and urges the detent part wayinto "the tip socket in forceful contact with the release 43. T he. detent recesses are dimensioned with respect to the spring and its rate to assure an effective lock manifest in the medial portion of the detent interposed between the op- ;posed surfaces 23 and 28 of the nested hammer members.

It will be realizedfrom what has been described above .thatwith the parts related as shown in FIG. 1, the detent can be released by forcefully applying a punch-like tool .to the free end of the pin 43A exposed at therarcuate face 33 of the hammer tip, advantageously with the tip at the By applying an adequate force directed As a consequence, the partsof the hammer have been unlocked, and the tip can be moved in a withdrawing direction.

Once the tip has been slipped past the depressed or released detent 37 sufficiently to present to the released detent a portion of theflat surfaceii at the bottom of the recess '26, it is no longer necessary to hold the detent in a depressed state by the aforesaid tool.

' Replacement operations of the kind herein considered are usually carried out at the top of the mill, that is, the end surface 23 of the shank is uppermost. Therefore, in positioning a new tip on the hammer shank, the detent and its spring are held .manually in a releasing position all the way back in the shank recess 35. The new tip is slipped on to the free end of the shank, while holding the detent released, until the seat 40 isrpresented to the detent, whereupon the detent is freed to snap into the opening 44 in the hammer tip.

It is not necessary under all circumstances to resort to the releasing pin 43. The primary advantage of this is that the pin portion 43A thereof fills the aperture 41 preventing the latter from being clogged by the material "being crushed in the mill. Where this possibility is not something to be reckoned with, the release stud 43 may be omitted with appropriatealterations in the detent, and the releasing tool when used will be entered in the aperture 41 to engage directly the face of the .detent inciden- --tal to releasing the'same.

Advantageously, and again taking into account the possibility of fines produced within the mill asa result of the crushing action, the spring 36 can be embedded in a solid body of rubber 45, FIG. 3, thereby assuring that the coils of the spring will not become clogged with solid particles interfering with spring action.

It Will be seen from the foregoing that the present invention makes it possible to replace the worn tip of a two-part'h-ammer with facility merely by moving a spring detent to .a released or inoperative position, whereafter the worn part can be slipped off the end of the shank .in a-direction normal to the longitudinalaxis of the shank. Ordinarily, the detent is effective to holdthe tip im- .mobilized on the working end of the hammer shank. Advantageously, the arms as 17 and 18 on the hammer shank are undercut or dovetailed at the surfaces facing the opening 14, to ineifect establish an undercut grip on the internal surfaces of the tip that are complemental thereto, thereby preventing the tendency for the end wallsfifiW and 31w, of the tip to spread dueto the appreciable centrifugal .forces' that are present when the hammer is in use.

.such changes and alterations as fall within the purview of the following claims.

I claim: 7

l. A two part hammer of the kind to be used ina hammer mill comprising a shank member adapted: at

one end to be secured on a shaft of the mill, and a re- .placeable tip member on the opposite end of the shank,

said members havingcomplemental interfitting parts slidably related to enable the tip to be slipped on and off said opposite end of the shank in a directionnormal to the longitudinal axis of the shank and firmly secured against displacement due to centrifugal forces in use, a

recessed spring detent including a boss and a related resilient element projecting the boss partly from one of the members, the other member along an axis parallel torthe longitudinal axis of the shank having a socket centered on the second-named axis for receiving the pro- .jected part of the boss locking the tip to the shank, and

an aperture in said other member extended from said socket to the exterior of said other member and-being of reduced diameter in comparison to said socket enabling a tool to be entered therein to engage and release said boss from said socket.

2. A hammer according'to claim 1 wherein the inter- 'fitting parts including projecting shoulders on oneof the .mernbers adapted to fit into. complemental grooves in the other member, and said shoulders having sloped surfaces. 7 I

3. A hammer according to claim 1 wherein the tip is recessed downwardly from the top thereof, said recess being open on one side of the tip to enable the'tip to be slipped onto the shank as aforesaid.

4. A two part hammer of the kind to be used in a hammer mill and comprising a shank member adapted at one end to be secured on a shaft of the mill, and a replaceable tip member on the opposite end of the shank, said members having complemental interfitting parts slidably related to enable the tip to he slipped on and off said opposite end of the shank in a direction normal to the longitudinal axis of the shank and firmly secured against displacement due to centrifugal forces in use, a spring detent including a boss and a spring element acting thereon disposed within a medially located opening at the lower face of the shank, said spring element normally projecting the boss partly beyond the lower face of the shank, a socket in the tip receiving the projected part of the detent boss, and a release stud in the socket of the tip includinga part at the bottom of the tip engageable by a tool to move the detent boss to a releasing position.

5. A replaceable tip for a two part hammer to be used in a hammer mill and comprising a body portion presenting an impacting face normally disposed generally in a vertical plane, and a lower face generally in a plane normal to the first-named face, said body portion being formed with a relatively large recess extending downwardly therein from the top of the tip, said recess also opening at one side of the tip, said tip being formed With a socket within said recess adapted to receive a locking detent carried by the shank of the hammer, and said tip being formed with an aperture which extends upwardly from the lower face of the tip to communicate with said socket to enable a pin or like tool to be entered therein to release the detent.

6. A tip according to claim 5 wherein the tip is provided with elongated grooves generally of dovetail configuration and opening at the open side of the tip, said grooves being of dovetail and configuration to interfit with complemental parts of a hammer shank thereby to resist the tendency for sections of the tip to spread due to centrifugal forces when in use.

7. A two part hammer of the kind to be used in a hammer mill and comprising a shank member adapted at one end to be secured on a shaft of the mill, and a replaceable tip member on the opposite end of the shank, said tip having a lower face and a pair of impacting faces in planes generally normal thereto, said tip being recessed downwardly from the top thereof to receive said opposite end of the shank, said members having complemental interfitting rib and groove elements slidably related within the area of the recess of the tip, said elements including projections on the tip having lower surfaces back-drafted to impart dovetail configuration thereto and to interfit with like surfaces on the hammer shank thereby to resist the tendency for sections of the tip to spread due to centrifugal forces when the hammer is in use, and the recess in said tip being open at one side of the tip to enable the tip to he slipped on and oil said opposite end of the shank in a direction normal to the longitudinal axis of the shank and firmly secured against displacement due to centrifugal forces in use,

said projections extending into said recess from opposite sides thereof and the back-drafted surfaces thereof slanting in the direction of said impact faces and being in planes generally parallel to said lower face and adapted to interfit with said like surfaces on said hammer shank, thereby to establish resistance to spreading of the hammer tip due to centrifugal forces.

8. A two part hammer of the kind to be used in a hammer mill and comprising a shank member adapted at one end to be secured on a shaft of the mill, and a replaceable tip member on the opposite end of the shank, said members having complemental interfitting parts slidably related to enable the tip to be slipped on and 0E said opposite end of the shank in a direction normal to the longitudinal axis of the shank and firmly secured against displacement due to centrifugal forces when in use, said shank at its lower end being formed with a medially located opening extending upward thereinto along an axis parallel to the longitudinal axis of the shank, a detent normally within said opening and having a portion partly projecting therefrom beyond the plane of the lower face of the shank, spring means within said opening in said shank normally positioning the detent as aforesaid, a socket within the tip aligned with said axis and adapted to receive said portion of the detent locking the tip to the shank, and an aperture in the tip in communication with the socket in the tip and of reduced diameter in comparison thereto enabling a tool to be entered therein to release the detent.

9. A hammer according to claim 8 wherein the aperture contains a detent release pin to be engaged by such a tool.

10. A hammer according to claimS wherein the spring means is in the form of a rubber block containing a coil spring.

11. A replaceable tip for a two part hammer to be used in a hammer mill and comprising a body portion presenting an impacting face, generally in a vertical plane, and a lower face generally in a plane normal to the first! named face, said body portion having a relatively large recess extending downwardly therein from the top of the tip, said recess also opening at one side of the tip, and a pair of projections within the tip projecting into said recess from opposite sides thereof and extended to said one side of the tip, said projections having oppositely directed back-drafted lower surfaces slanting in the direction of said impact face and disposed in planes generally parallel to said lower face and adapted to mate with interfitting parts of complemental shape carried by the shank of the hammer, thereby to establish resistance to spreading of the hammer tip due to centrifugal forces when the hammer is in use.

References Cited by the Examiner UNITED STATES PATENTS 829,862 8/06 Ely. 2,152,332 3/39 Smith 241197 2,620,989 12/52 Keiper 241-197 I. SPENCER OVERHOLSER, Primary Examiner.

ROBERT A. OLEARY, Examiner. 

5. A REPLACEABLE TIP FOR A PART HAMMER TO BE USED IN A HAMMER MILL AND COMPRISING A BODY PORTION PRESENTING AN IMPACTING FACE NORMALLY DISPOSED GENERALLY IN A VERTICAL PLANE, AND A LOWER FACE GENERALLY IN A PLANE NORMAL TO THE FIRST-NAMED FACE, SECOND BODY PORTION BEING FORMED WITH A RELATIVELY LARGE RECESS EXTENDING DOWNWARDLY THEREIN FROM THE TOP OF THE TIP, SAID RECESS ALSO OPENING AT ONE SIDE OF THE TIP, SAID TIP BEING FORMED WITH A SOCKET WITHIN SAID RECESS ADAPTED TO RECEIVE A LOCKING DETENT CARRIED BY THE SHANK OF THE HAMMER, AND SAID TIP BEING FORMED WITH AN APERTURE WHICH EXTENDS UPWARDLY FROM THE LOWER FACE OF THE TIP TO COMMUNICATE WITH SAID SOCKET TO ENABLE A PIN OR LIKE TOOL TO BE ENTERED THEREIN TO RELEASE THE DETENT. 